The albino rat is commonly-used subject in experiments investigating the effects of hypothalamic (HTH) lesions or electrical stimulation on feeding behavior. However, almost nothing is known concerning the effects of such HTH manipulations on the viscera (particularly the gastrointestinal tract) of this animal. Experiments are proposed to investigate a) whether HTH lesions or electrical stimulation reliably produce GI pathology (ulcers, hemorrhages); b) the extent to which GI pathology is related to the aphagia which appears following lateral HTH lesions; and c) whether "rewarding" and "aversive" HTH electrical stimulation have differential effects on the production of GI pathology.